How to fix my 5V, 2.5amp adapter.

There is very likely a fusible link somewhere inside the wall-wart that mig ht look something like this:

Use your ohm meter to check and see if one is there and if it is open.

Good luck with it.

Peter Wieck Melrose Park, PA

One of the capacitors that goes high esr and causes a power supply to die if it cools off doesn't show any physical deterioration. Usually

Bottom line...buy the new supply. Problem with that one is the plug on the end is different from most other router power supplies. Get the right one and be done with it.

I fix wall warts all the time for my own use. I'd never sell a gizmo with a power supply that I repaired. Too much liability involved.

Most fail with shorted input diodes, but that also blows the fuse. I've been fixing stuff for almost half a century, but working on line-connected stuff still scares the hell out of me...and I've got a completely isolated scope probe system. Even if you do find out what's broke, where are you gonna get the replacement part? Putting it back together is problematic. What happens if you try to unplug it and the glue breaks...you end up with AC in your hands...not fun.

Look at the risk/reward ratio. Best that can possibly happen is you save $7.50. Worst is electrocution? burning down your house? For stuff connected directly to the line, if you don't know what you're doing, keep it that way.

Ummm... perhaps Google for "JTA0302 repair"?

Drivel: Here's my collection: with a few wall wart repairs.

So you're suggesting there was no surge, but the lack of power let the PS cool off and the capacitor fail! I never would have thought of that. Also, you name the same cap that the url Jeff gave found was bad (along with the zener diode).

And you're right, it looks fine.

I recognize the sarcasm. ;-)

It never occurred to me to do that. Wow, the perfect page.

That's it all right. A slightly different arrangment, but all the same parts.

And a schematic too! I have to spend a bunch of time looking at that.

No kidding!

Thanks, and thanks all.

I was on the phone with a very polite but useless support personality possibly in India. I hope you don't mind me taking out my frustrations on you.

Yep. I usually don't get that lucky. I recently tried to repair one of those by replacing 3 of the caps mentioned. It didn't work. Of course, I didn't bother searching for info until after I had given up and recycled the power supply. Do like I say, not like I do.

There are A through E variations. I've only seen B and C which look like the same board layout, but built by different contractors. I don't know if there are any component value changes or schematic variations.

You should be able to get some theory of operation in the data sheets and app notes for the UC3843B chip:

I don't know why I bother trying to fix those. It's certainly not making me any money. Worse, I've accumulated a fairly large collection of wall warts that really need to be recycled instead of occupying space.

"One day, son, all of these perfectly good A.C. adapters, which have long outlived the products they were originally designed for, will be yours."

Its amazing how you guys can find schematics to these things.

I would check the primary side of the transformer, make sure it didn't get opened from a latch on.

Also check that little blue thingy that is attached to the line fuse feeding the common choke. You may need to do that under power via a volt meter.

Have fun.

Jamie

It's actually quite easy. Instead of searching the web, I do an image search. Photos, schematics, disassembly instructions, and such are much easier to find using images than text. You can text search for "xxxxx schematic" but schematics are rarely titles with the word "schematic" on the page.

If the photo is not quite what I want, such as Google image search find a thumbnail instead of a full size image, I use one of several reverse image searches to find the original: etc...

I'll keep that in mind, Thanks

Jamie

Me too. Thanks.

One more question.

If I couldnt' find a power supply for the router, until I bought a new one, could I have just unplugged the wire from the DSL modem to the router and plugged it into the computer? The only thing I'm doing wirelessly now is print, and I don't print very often.

This idea kept popping in my head and then disappearing.

Sigh.

Yes. 5V from the computer is the same as 5v from the Dlink wall wart. I have a cable with a Molex connector to adapt from the disk drive power connectors to some power plugs and cables that I hacked off some dead wall warts. This kludge makes a handy adapter cable for exactly what you're doing. I've used it when a customers wall wart dies, and I need something temporary until I can either fix or replace the original wall wart. If you can find the right size power plug, it should work.

You probably have a black hole in your head. Black holes will suck both good and bad ideas equally so don't use the prevalence or disappearance of the idea as a figure of merit.

Sorry, I still don't follow: what are you using as your search criterion? I see how you might get disassembly instructions (or lots of sales pitches!) using a photo of the outside of the device, but schematics?

Mike.

This is the price you pay for your earlier sarcasm.

No, no 5v at all. I mean eliminating the router and going straight from the DSL modem to the network card in the computer. That's the default, isn't it? It's only been 8 years but I can't remember.

Maybe I can get some Gorilla Tape. It's black too so it won't show that much.

Apparently it just cooled off!

I did that. Should be here on Friday.

In the same way that planning for a vacation is almost as much fun as the vacation, it seems yesterday planning to repair the PS was 1/3rd the fun of actually doing it, plus I don't have a zener diode and even the parts I do have become a little hard to find.

They have the exact one, with the green plug showing in the photo.

If I did it, I'd do it right. I know what I'm doing. Not knowing which part to replace doesn't mean I don't know what I'm doing.

No, you do not want to power off the USB port of the computer.

that supply is over 2 amps and most likely for good reason.

My router requires 1 amp minimum while the USB ports on most PC's are 500mA (1/2 amp)

You can have a USB port that has charging options, and also they do come with higher current but that is not the norm.

USB 3.x for the most part I understand have more powwer.

You are better off not chancing it.

Jamie.

If you are talking about using the data cable and removing the router from the system, you should be able to do it with out any problems. I do it from time to time just to check the download and upload speeds.

It's a very common failure on supplies that run 24/7 to fail to restart aft er a cool down period.

Get any old hair dryer and give it a nice sauna for a few minutes, then plu g it back in. If it starts, it's a high ESR cap in about 95% of the time.

ed

That will work if:

1. If you're using PPPoE or PPPoA that require a login and password, it will work if those are saved in the DSL modem or in the computah. However, if you saved them in the router, you'll have to temporarily move them.
2. If you trust your unspecified operating system to be secure without the hardware firewall in the router. The DSL modem passes all ports, even if it has internal DHCP, so your computah's firewall does all the work.
3. If your DSL modem is independent of your router and doesn't require a hack saw to seperate them.

Can't you find a 5V power source and a power jack and do it correctly? This is a repair newsgroup, not a substitution newsgroup. A 5v 2A cell phone or tablet charger should work. Worst case is borrow the 5V from the PC. Do something, even if it's wrong.